If you’re a fan of butter-flavored microwave popcorn, a new study finds a flavoring used in the product may trigger Alzheimer’s disease.

University of Minnesota drug-design expert Robert Vince, PhD, and colleagues found that diacetyl causes brain proteins to misfold into the Alzheimer’s-linked form called beta amyloid. Vince’s team also found that diacetyl has an architecture similar to a substance that makes beta-amyloid proteins clump together in the brain — clumping being a hallmark of Alzheimer’s disease.

Even more, the popcorn butter flavorant can pass through the blood-brain barrier and can inhibit the brain’s natural amyloid-clearing mechanisms.

Diacetyl, already linked to lung damage in people who work in microwave popcorn factories, is also used to produce the distinctive buttery flavor and aroma of margarines, snack foods, candy, baked goods, pet foods, and even some chardonnays.

The study, announced last week, appears in ACS’s journal Chemical Research in Toxicology.

However it’s not all bad news for popcorn.

LEARN MORE ABOUT ALZHEIMER’S DISEASE

A group of  scientists recently claimed popcorn the perfect snack food after discovering that the hulls contain more antioxidants than fruits and vegetables. But cooking popcorn in a pot of oil, slathering on the butter, or pouring on the salt can quickly cancel out their nutritional benefits, the researchers add.

The healthiest way to enjoy the snack food: make it air-popped.